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Date: Wed, 23 Dec 2020 12:33:35 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf stat: Create '--add-default' option to append
default list
On 12/23/2020 8:56 AM, Jin, Yao wrote:
> Hi Arnaldo,
>
> On 12/23/2020 12:15 AM, Arnaldo Carvalho de Melo wrote:
>> Em Tue, Dec 22, 2020 at 09:11:31AM +0800, Jin Yao escreveu:
>>> The event default list includes the most common events which are widely
>>> used by users. But with -e option, the current perf only counts the events
>>> assigned by -e option. Users may want to collect some extra events with
>>> the default list. For this case, users have to manually add all the events
>>> from the default list. It's inconvenient. Also, users may don't know how to
>>> get the default list.
>>>
>>> It's better to add a new option to append default list to the -e events.
>>> The new option is '--add-default'.
>>>
>>> Before:
>>>
>>> root@...-ppc:~# ./perf stat -e power/energy-pkg/ -a -- sleep 1
>>>
>>> Performance counter stats for 'system wide':
>>>
>>> 2.05 Joules power/energy-pkg/
>>>
>>> 1.000857974 seconds time elapsed
>>>
>>> After:
>>>
>>> root@...-ppc:~# ./perf stat -e power/energy-pkg/ -a --add-default -- sleep 1
>>
>> I thought about:
>>
>> perf stat -e +power/energy-pkg/ -a -- sleep 1
>>
>
> I was surprised to see that '+<event>' syntax had been supported.
>
> root@...-ppc:~# ./perf stat -e +power/energy-pkg/ -a -- sleep 1
>
> Performance counter stats for 'system wide':
>
> 1.99 Joules +power/energy-pkg/
>
> 1.000877852 seconds time elapsed
>
> root@...-ppc:~# ./perf stat -e +power/energy-pkg/,+cycles -a -- sleep 1
>
> Performance counter stats for 'system wide':
>
> 2.00 Joules +power/energy-pkg/
> 13,780,620 +cycles
>
> 1.001639147 seconds time elapsed
>
> Are there any scripts or usages need the prefix '+' before event? I don't know. But if we append the
> '+<event>' to the default event list, will break something potentially?
>
>> Which would have its counterpart:
>>
>> perf stat -e -cycles -0a --sleep 1
>>
>> To remove an event from the defaults, perhaps to deal with some specific
>> hardware where the default or what is in -d, -dd, -ddd, etc can't all be
>> counted. I.e. - and + would remove or add from whaver list was there at
>> that point.
>>
>> - Arnaldo
>
> Yes, + and - are more flexible solution. Just for above question, will '+<event>' break existing
> usage? And for '-', I don't know if user can remember clearly for what the events are in default list.
>
For '-', another difficulty is it may conflict with the hardware cache event.
Say we remove the "- { return '-'; }" from parse-events.l, such as:
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 9db5097317f4..145653d1ce16 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -387,7 +387,6 @@ r{num_raw_hex} { return raw(yyscanner); }
{name} { return pmu_str_check(yyscanner, _parse_state); }
{name_tag} { return str(yyscanner, PE_NAME); }
"/" { BEGIN(config); return '/'; }
-- { return '-'; }
, { BEGIN(event); return ','; }
: { return ':'; }
"{" { BEGIN(event); return '{'; }
The syntax of '-<event>' is supported.
root@...-ppc:~# ./perf stat -e -cycles -a -- sleep 1
Performance counter stats for 'system wide':
14,008,859 -cycles
1.001471494 seconds time elapsed
But the parsing of hardware cache event would be failed. :(
root@...-ppc:~# ./perf stat -e LLC-stores -a -- sleep 1
event syntax error: 'LLC-stores'
\___ parser error
That complicates things. :(
Thanks
Jin Yao
> Thanks
> Jin Yao
>
>>> Performance counter stats for 'system wide':
>>>
>>> 2.10 Joules power/energy-pkg/ # 0.000 K/sec
>>> 8,009.89 msec cpu-clock # 7.995 CPUs utilized
>>> 140 context-switches # 0.017 K/sec
>>> 9 cpu-migrations # 0.001 K/sec
>>> 66 page-faults # 0.008 K/sec
>>> 10,671,929 cycles # 0.001 GHz
>>> 4,736,880 instructions # 0.44 insn per cycle
>>> 942,951 branches # 0.118 M/sec
>>> 76,096 branch-misses # 8.07% of all branches
>>>
>>> 1.001809960 seconds time elapsed
>>>
>>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>>> ---
>>> tools/perf/Documentation/perf-stat.txt | 5 +++++
>>> tools/perf/builtin-stat.c | 4 +++-
>>> tools/perf/util/stat.h | 1 +
>>> 3 files changed, 9 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
>>> index 5d4a673d7621..75a83c2e4dc5 100644
>>> --- a/tools/perf/Documentation/perf-stat.txt
>>> +++ b/tools/perf/Documentation/perf-stat.txt
>>> @@ -438,6 +438,11 @@ convenient for post processing.
>>> --summary::
>>> Print summary for interval mode (-I).
>>> +--add-default::
>>> +The default event list includes the most common events which are widely
>>> +used by users. But with -e option, the perf only counts the events assigned
>>> +by -e option. This options appends the default event list to the -e events.
>>> +
>>> EXAMPLES
>>> --------
>>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>>> index 89c32692f40c..6ac7b946f9a7 100644
>>> --- a/tools/perf/builtin-stat.c
>>> +++ b/tools/perf/builtin-stat.c
>>> @@ -1173,6 +1173,8 @@ static struct option stat_options[] = {
>>> "print summary for interval mode"),
>>> OPT_BOOLEAN(0, "quiet", &stat_config.quiet,
>>> "don't print output (useful with record)"),
>>> + OPT_BOOLEAN(0, "add-default", &stat_config.add_default,
>>> + "add default events"),
>>> #ifdef HAVE_LIBPFM
>>> OPT_CALLBACK(0, "pfm-events", &evsel_list, "event",
>>> "libpfm4 event selector. use 'perf list' to list available events",
>>> @@ -1755,7 +1757,7 @@ static int add_default_attributes(void)
>>> free(str);
>>> }
>>> - if (!evsel_list->core.nr_entries) {
>>> + if (!evsel_list->core.nr_entries || stat_config.add_default) {
>>> if (target__has_cpu(&target))
>>> default_attrs0[0].config = PERF_COUNT_SW_CPU_CLOCK;
>>> diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
>>> index 9979b4b100f2..6ccc6936348c 100644
>>> --- a/tools/perf/util/stat.h
>>> +++ b/tools/perf/util/stat.h
>>> @@ -123,6 +123,7 @@ struct perf_stat_config {
>>> bool metric_no_merge;
>>> bool stop_read_counter;
>>> bool quiet;
>>> + bool add_default;
>>> FILE *output;
>>> unsigned int interval;
>>> unsigned int timeout;
>>> --
>>> 2.17.1
>>>
>>
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